Product, version and build:
64 bit version of product: 5.5.155
Operating system: Win10x64

*** Please add details and screenshots as needed below. ***

I published a GUI that had a RichTextBox control with DetectUrls = True with a link inside of it like in the example below:

"If you would like more information, click this link: <https://example.com/info.html>"

It worked great. But now, I needed to add a couple of additional links as in the example below:

"If you would like more information, click this link: <https://example.com/info.html>
If read the policy, click here: <https://example.com/sure.html>
For further questions, click here: <https://example.com/notsure.html>"

It compiles fine and looks good.. but none of the links work. Am I doing something wrong or is each RichTextBox limited to finding one link?

Just keep in mind, when working with Windows Form controls, you're dealing with events. So, you need to add the event for the when you click the Url link.
This is the "LinkClicked" event.

This is well documented in the Microsoft Doc: https://docs.microsoft.com/es-es/dotnet/api/system.windows.forms.richtextbox.detecturls?redirectedfrom=MSDN&view=netframework-4.7.2

Now, to add the event to the form, just Right-Clicked on the RichTextBox control, then select "Add Events".
Select (Checked) the "LinkClicked" event, and this will be added to the script section of the control.